PEIGNEUX J. P. Phy. Div., Lab. D'Annecy-Le-Vieux De Phys. Des Particles, LAPP, 物理部(アネシー・フランス), 教授
STROOT J. P. PPE Div., CERN and Inst. Interuniv. for Nucl. Sci., IISN, Brussels, 物理部(ジュネーブ・スイス), 教授
PROKOSHKIN Y 高エネルギー物理学研究所, 物理部(プロトビノ・ソ連), 教授
KAWAI Hideyuki Coll. of Art and Science, Chiba University, 教養部, 講師 (60214590)
SHIMIZU Hajime Dept. of Physics, Yamagata University, 教養部, 助教授 (20178982)
NAKAMURA Teruo Faculty of Engineer, Miyazaki University, 工学部, 教授 (00025305)
INABA Susumu Physics Department, Nat. Lab. for High Energy Physics, KEK, 物理研究部, 助教授 (10013434)
TSURU Tsuneaki Physics Department, Nat. Lab. for High Energy Physics, KEK, 物理研究部, 助教授 (60044781)
KOBAYASHI Masaaki Physics Department, Nat. Lab. for High Energy Physics, KEK, 物理研究部, 助教授 (40013388)
PROKOSHKIN Yu. D. Department. of Phys, Inst. for High Energy Physics, IHEP, Protvino
The GAMS Collaboration aims at searching for new meson states produced by the central collisions and the charge exchange process of pip and pp interactions. It consists of the two parts, i. e. one is the experiment, SERP-E-172 which uses 32 GeV pions produced by the 70 GeV Proton Synchrotron and the GAMS 47pi Spectrometer at IHEP (Protvino, Russia) in the framework of the sixth IHEP and CERN joint experiment programs and the other is the Experimental project, NA12/2 which uses 300 GeV pions and 450 GeV protons produced by the Super Proton Synchrotron. and the GAMS 4000 spectrometer at CERN. GAMS is a nickname of the spectrometer which detects energy and position of high energy gamma-rays decaying from neutral meson states produced in the reactions.
The KEK group joined the collaboration in 1998 and have continued the work. Meanwhile, the agreement between KEK and IHEP have been signed up on the scientific collaboration for the GAMS experiment in 1990.
We performed the experimental runnin
g of 96 effective days between May and September in 1991 with the upgraded spectrometer system of GAMS 4000 at CERN and collected 80 millions of triggered events on the central collision production. During the run, we tested the new data acquisition system which has been developed by CERN and KEK groups and will be instaled in the next run of 1992. At IHEP, we performed the data taking run of 30 effective days with 32 GeV negative pions and the GAMS 4pi spectrometer. We have upgraded it for detecting charged particles decaying from meson states by installing large drift chambers. The readout system of signals of them has been developed and prepared by the KEK group. Partial wave analyses of the data are now under way.
Meanwhile, we have analyzed etaeta' and omegapi^0 system of 1984-1987 data produced in the pip charge exchange processes. X (1910) has been found in the etaeta' final state. The state is expected to be a qq exotic one. X (2200) in the omegapi^0 final state has also been found. It has the same quantum numbers that of p (770) and is considered to be a radial and orbital excitation of p (770). These results of the analyses have been reported at fhe conference, Hadron9l and have been submitted for publication Less